Expert advice about the best doors for blocking sound, including best sound reducing materials, sealing around a door, and other noise control measures.
Doors play an integral role in controlling the movement of sound through a house. They are typically the thinnest barrier in a wall and, when it comes to blocking sound or reducing noise, they don’t benefit from the thicker—sometimes insulated—construction of walls. Here we’ll looking at the best doors for blocking sound and techniques for reducing noise.
A typical interior door has a hollow core—inner cardboard honeycomb cores surrounded by a softwood frame. The door’s surfaces are faced with very thin wood veneers. Between the thin surfaces and the air-filled core, there isn’t much there to block the movement of sound because they’re built like drums.
Solid-core exterior or interior doors block noise more effectively because of their density. Manufacturers sell many types, ranging from expensive hardwood to more affordable Medium Density Fiberboard (MDF). Though most interior doors are 1 3/8-inch thick, exterior doors are typically 1 3/4-inch thick. The thicker the door, the better it reduces noise transfer.
Of course, it doesn’t matter how the door is built if it’s open, right? Similarly, if gaps exist around the edges or between the bottom of the door and the floor, sound will sneak around the door from one room to the next.
So the door should fit the jamb tightly, and weatherstripping should seal around its edges. Rubber or vinyl bulb door weatherstripping and a door-bottom weatherstripping sweep do a good job of sealing around the perimeter of a door to block noise. If you need a door sweep that doesn’t drag along the floor, investigate an automatic door sweep that seals the bottom of the door only when the door is closed.
You can buy recording-studio-grade door noise-reducing materials online as an acoustic door seal kit.
Sound-blocking materials are rated by an STC (Sound Transmission Class) rating. If you were to replace a hollow-core interior door that has an STC of less than 20 with a solid-core door that is properly weatherstripped, what would be the result? According to the National Wood Window and Door Association, “If you did all of this, you could probably end up with an STC rating of 34 to 36.” For more about STC ratings, please see Soundproofing Walls & Ceilings.
When planning for new doors and windows, also consider where sound travels. If possible, stagger doors along a hallway and arrange their swing so that they don’t deflect sound into adjoining rooms. Choose hinged doors; avoid sliding, bi-fold, and pocket doors that not only make noise themselves but also don’t seal as well as the swinging type. To keep a hinged door from squeaking, all you need to do is spray the hinges with a little WD-40 or penetrating oil.
Featured Resource: Find a Pre-Screened Local Soundproofing Contractor